so this just happened....

[Beater]

my happy little speedster isn't happy, and isn't speedstering very good at the moment. kids managed to blow apart the transmition. and I meen blow apart the transmition gears on the ground, bottom of the case laying on the ground. so another winter project. got another trans from a friend and it looks ok under first inspection. my question is, what is there to do, what should I be doing to modernize it up like better seals and stuff before I put the next one in? if anything.